1. Field of the Invention
This invention pertains to the field of motorcycles and their components. More particularly, the invention pertains to a novel modular carrier ring which is mountable on one or both sides of a motorcycle wheel hub for supporting accessories such as the front and rear wheel brake rotors and the rear wheel drive sprocket and/or drive pulley.
2. Description of the Prior Art
Virtually all chain-drive or belt-drive motorcycles are driven by an open loop of chain or a rubber or composite material belt stretched between the driving sprocket, extending from the motorcycle engine, to a driven sprocket or pulley located on the hub of the rear wheel of the motorcycle. In addition, almost all motorcycles utilize disc brakes on both wheels wherein a brake disc is located on the hub of both front and rear wheels.
Motorcycle wheels generally comprise a central cylindrical element called a "hub" that has a dual function, namely centrally anchors a plurality of spokes or other wheel supporting elements attached to a circularly peripheral rim that ultimately supports a tire thereabout and holds and securely mounts the brake rotor in the front wheel and mounts a brake rotor and a drive sprocket or pulley in the rear wheel. The hub generally contains sleeve or ball-bearing axle support bearings and seals that surround an axle on which the wheel turns. Hubs are made in one, two or more pieces that are traditionally designed personally for each manufacturer and for each type motorcycle.
Since their introduction, motorcycles have become quite sophisticated and have components that are specially made for different environments. For instance, many manufacturers produce rim-tire combinations that find specific use on asphalt tracks as opposed to dirt tracks. Other combinations find specific use on cross-country trips and tracks containing obstacles requiring the motorcycle to be turned sharply about them or thrust into the air to jump them. A motorcyclist thus may find his or her ability to compete in certain venues limited by their ability to own the many required wheel sets (hub-rim-tire combinations). Unfortunately, manufacturers of these combinations design the components individually for each model motorcycle and, in many cases, for each year of a specific model. Without any commonality between the combinations, such a practice often raises the total cost of procuring additional wheel sets beyond the financial means of the racers.
There have been attempts to design a hub-spoke-rim combination in a modular format that allows for improved economics in this area of the motorcycle art. For instance, U.S. Pat. No. 4,508,392 discloses a wheel hub including a structure for attachment of accessories including a pair of bushings for insertion on each side of the wheel and for bolting together to form a hub. The separately bolted parts have drive sprockets and other external components formed integral with the hub-halves to reduce the number of components needed to attach brake discs and sprockets to the hub. Unfortunately, each exterior part requires a special half-hub so that the overall cost of the assembly and the time to install it are not noticeably reduced over present practice.
U.S. Pat. No. 5,372,407 discloses a motorcycle wheel hub made of two halves with internal members for coupling them together and holes in the halves for anchoring spokes. This invention requires assembly by pressing the two halves together to engage the coupling members. Such a combination, however, requires mounting benches and special equipment to combine the components and this equipment is often not available at racing venues.
U.S. Pat. No.5,988,613 discloses a wheel hub and brake disc arrangement for a vehicle wheel utilizing a lock ring to permit limited axial loading of the brake disc during use of the wheel. While this is another attempt to reduce the complications of hub mounting, the lock ring is subject to disengagement under the significant stresses of motorcycle racing. Accordingly, there remains a need for a simplified means of mounting a brake disc to a wheel hub without the need for extra parts and components.